The Florida Health Department and state officials have announced that they have identified four cases of Zika virus infection that were most likely transmitted locally. These cases are in Wynwood, an area just north of Miami

This is probably the first time that mosquito-borne transmission of Zika virus has happened in the continental US.

The CDC and Florida are saying “likely” and “probably” because, although they cannot yet prove these individuals were bitten by infected mosquitoes, there seems to be no other method of transmission in these cases, and the mosquito that carries the virus does live in the area.

However, this does not mean that the Zika virus will become widespread in the US.

The Zika virus is transmitted a few ways. The most common way for people to get the Zika virus is to be bitten by an infected Aedes species mosquito (Ae. aegypti and Ae. Albopictus).

This mosquito doesn’t like the climate in all parts of the US. Much of the northern area will not be at risk from this mode of transmission.

Also, this mosquito never travels more than 150 meters its entire life. That’s less than 1/10th of a mile. It usually travels far less than that distance.

The West Nile virus, on the other hand, was able to pretty much cover the US because the virus can be transmitted from an infected mosquito to a bird, which then flies off quite a distance before landing and getting bitten by a different mosquito, which then becomes infected. That mosquito, in turn, bites another bird. This cycle hopscotches its way across the US, spreading disease from bird to mosquito to bird to mosquito.

The mosquitoes also infect humans and other mammals with West Nile virus.

The mosquitoes that carry the Zika virus don’t work that way. They prefer to only bite humans.

Another reason the Zika virus will probably not explode across the US is because where the mosquito lives, people use screens across their windows and doorways, and they use air conditioning. It’s more difficult for the mosquito to get into the houses.

There are other ways for the Zika virus to be transmitted.

An infected pregnant woman can pass it to her fetus during pregnancy or around the time of birth.

An infected individual can pass the virus through sex with their partner. An infected person may or may not be symptomatic—they can still transmit the virus. It appears that four out of five infections are asymptomatic. One cannot assume that a person is virus-free just because they don’t seem to be sick.

An infected person may donate blood and the virus can then be passed through blood transfusions.

This virus is under a lot of scrutiny. New methods of transmission may be identified, but these are the primary methods at this time.

Now we have an idea of how it’s transmitted. What can we do about it?

Where pockets of infection have occurred, the state and local authorities have started aggressive mosquito control, including spraying and going door to door to alert residents to standing water. Mosquitoes love to lay eggs in standing water—making sure there is none helps to control the mosquito population.

We all need to prevent mosquito bites by using insect repellent containing DEET, wearing long sleeves and pants, and staying indoors unless covered and protected. This is particularly true for pregnant women, and for those living in areas where these mosquitoes are common.

Pregnant women are harder hit by flu than women of the same age who are not pregnant. Their symptoms are usually more severe, there are more hospitalizations, and they’re at higher risk of premature delivery or even death.

Although the infection doesn’t travel from the woman to her fetus, if the mom-to-be is infected, her infection may indirectly hurt the fetus.

A premature delivery may mean the baby is too small, or underdeveloped. It can even mean death for the baby. If fever is present, mom’s infection can also lead to an assortment of abnormalities in the baby.

Why is this? Well, we can’t say for sure.

Part of a pregnant woman’s immune system is changed, or weakened, during pregnancy. This happens so that the woman’s body won’t attack the fetus as a foreign invader.

This altered immune state may allow a flu virus to attack, causing harm to the pregnant woman.

It’s also possible that part of the immune response is actually boosted during pregnancy, causing an increase in inflammation in the lungs when a pregnant woman is infected with a flu virus.

This in turn may be causing the increase in death and illness found in some flu-infected pregnant women.

The fact that pregnant women’s organs are squished may also increase the risk of pneumonia or other problems. Also, because of the increased blood volume, a pregnant woman’s lungs are a little “wetter” and less capable of resisting a severe infection.

Could be, may, might — that’s not what we want to hear. We want definite reasons so that we can use definite means to prevent all of this.

Unfortunately, it’s just not that simple.

If you’re pregnant, be extra cautious when it comes to flu. Call your provider as soon as you have symptoms — early treatment makes a big difference.

CDC recommends that if you are pregnant and have any of these signs, you should call 911 right away:
• Difficulty breathing or shortness of breath
• Pain or pressure in the chest or abdomen
• Sudden dizziness
• Confusion
• Severe or persistent vomiting
• High fever that is not responding to Tylenol® (or store brand equivalent)
• Decreased or no movement of your baby

CDC recommends that individuals six months of age and older be immunized each year against flu.

Immunization and clean hands are the two best tools to prevent infection. Check with your healthcare provider to see about staying up-to-date on your immunizations.

Disclaimer

The information on PKIDs' Blog is for educational purposes only and should not be considered to be medical advice. It is not meant to replace the advice of the physician who cares for you or your child. All medical advice and information should be considered to be incomplete without a physical exam, which is not possible without a visit to your doctor.